Here is the latest 55 stable version of 32-bit or here is the latest 55 stable version of 64-bit. The directories are divided by languages, so if you want the English version look in the directory en-US (x86) or en-US (x64).It is never a good idea to migrate your profile from one version to another, especially if it is a previous version.I recommend that you install the version you want in another location and create a new profile, to avoid possible problems.For example: I have installed two versions of Firefox like this:

You will have to create a new profile after installing another version, so they do not mix (type in the address bar "about:profiles")

and shortcuts targeted at different profiles like this:"…firefox.exe" -P "<profilename>"

(to know the name of your profiles also in "about: profiles")For example my profiles are called "55.0.3" and "56.0.1" respectively, so the shortcuts are as follows:"C:\Program Files\Mozilla\Firefox\55.0.3\firefox.exe" -P "55.0.3""C:\Program Files\Mozilla\Firefox\56.0.1\firefox.exe" -P "56.0.1"

James wrote:Firefox 52 ESR will update up to 52.8.0 ESR in May 2018 unless Mozilla by chance extends support.

Before that happens, users need to be wary of a Mozilla offer to upgrade to FF59 around the begiining of March. Take care to refuse it so that FF can just upgrade to 52.7. See the "Note" by Aris-t2 (7th paragraph down) on this site: https://github.com/Aris-t2/ClassicTheme ... issues/299